Caroline Dubois' Olympic adventure was harshly ended on Tuesday morning after a split-decision defeat in the quarter-finals.
Team GB's Dubois lost to Thailand's Sudaporn Seesondee 3-2 in the women's lightweight tournament, ending her dreams of taking home a medal.
She was left visibly stunned when the scorecards were revealed after a close fight which could have gone either way.
Dubois, aged 20, is the Youth Olympics champion and had shone at Tokyo 2020 so far in wins over Kosovo and the USA.
The defeat ends an exhilarating journey for the sister of heavyweight contender Daniel Dubois. Her first fights as an adult amateur came in the Olympic qualifiers last year and, after the Games were postponed, she then defeated the bronze medallist from Rio 2016 to qualify for Tokyo.
Team GB are guaranteed six boxing medals after Galal Yafai advanced into the men's flyweight semi-final.
Birmingham's Yafai, a veteran of Rio 2016, outworked Cuba's Yosbany Veitia to win a split decision and is now set to bring home at least a bronze.